Burning Candle - Combustion Process

Purpose

To demonstrate features of the burning process and to debunk myths about this supposedly well-known demonstration.

Equipment

Burning candle apparatus with colored water.

Setup Time

5 min.

Images

Description

A common pre-college experiment is to burn a candle inside of a bottle which has been turned upside down over a container of water. The water supposedly rises about one-fifth of the way up the bottle, indicating that the oxygen, about one-fifth of the air in the atmosphere, has been "used up" in the combustion process. The candle in our experiment is placed inside the sealed tube containing air above a colored water bath, and is then ignited by a hot wire. The water level goes down initially, then returns to its original level just after the candle goes out. There is NO CHANGE in the water lev